Itsallgood995

Motor is hydrolocked & the oil level is high. It wasn’t overfilled & there are no signs of water in the oil. Why would it go up like that w/ no signs of water? Compression varies from 115 to 160psi. The motor only has 100hrs on new top end. It has the 454HO cam, which I thought, shouldn’t have any reversion issues but now I wonder. Boat still has through prop exhaust.

My daughter was pulling me when she ran aground in the mud. I think this probably blocked some of the water passages & overheated the motor & thus blowing the head gaskets. Both sides of the motor had water in the cylinders. Just want to make sure this is a overheat issue & not something else like reversion, detonation, etc. What all should I check?

JaayTeee

I have heard of this happening a couple of times
from people I know after they overheated and shut the
engine off.

What happened was that the
engine "dieseled", ( ran on) but kicked backwards,
water is then drawn back into the exhaust.

Itsallgood995

So the motor ingested all the water between the flappers in the y-pipe & the risers?

Any idea on the high oil level?

eichhoma

iTrader: (1)

If you are sure it is not water.... then its probably fuel... pull the dipstick and take a wiff... does it smell like gas?
If so, GET THAT CRAP OUT OF THERE..... fuel dilluted oil will trash a motor fast. Since you have a new top end, did the carb get rebuilt? how is the tune? What do the plugs look like? are they all fouled out?

Ahh... just read yo overheated and had water in the cylinders.... that will do it, it will clear the rings and run down the cylinder walls into the oil pan... but you said earlier it was NOT water? Its either water or fuel; both equally destructive.

stevesxm

you have either rotted away an interior section of the intake manfifold towards the rear cylinders or rotted away a part of the exhaust manifolds and filled up a couple of cylinders w/ water which ran down by the rings and filled up the oil pan. do two things right away...

get the plugs out and rotate the motor by hand until the cylinders are clear and fill w/ oil and then get the heads off ASAP. if the motor won't tturn by hand then you have either rusted the valves to the guides or the rings to the bores and every day you wait costs you many more dollars in repair.

if you rust up those bores badly it goes from a couple hundred to fix to a couple thousand very very quickly.

Itsallgood995

I'll drian the oil & whatever else is in there & pull the heads tonight. Its not milkshake & doesn't smell like fuel. All the plugs where wet & showing signs of rust. The motor freely turns over w/ the plugs removed.

JaayTeee

Without cooling water in the exhaust, the
flappers in the y pipe don't live too long.


The one's that I had dealings with were sea pump
failures, and after the impellers were changed,
and the water was purged from the cylinders,
and oil was changed, they ran fine.

The key here is that this was all handled quickly,
they didn't let things sit and rust.

Thunderstruck

What signs did you check for water in the oil? My exhaust leaked and put water in the oil pan past the rings. The dipstick looked normal. For some reason the oil pushed up into the dipstick without any water. Rub your finger around the oil fill hole (inside) on the valve cover and check for cheese.

Itsallgood995

No water bubbles, no milkshake... just looks like clean oil. I would think it would have mixed up when I did the compression check & looked like milkshake. I'm going to run home @ lunch & drain it.

Should I pour diesel in it & crank it over & then drain that? I read that will displace any water & lubricate everything?

stevesxm

the ones that i have seen like this have the water and oil seperate cleanly w/ the water sitting on the bottom. when you drain it, you will see clean water come out... then the oil. after you get the water out and fix whats wrong, i would just run some clean lightweight oil thru it for a couple of changes... just run it to temp at idle for 20 or 30 minutes then drain then repeat .

the trick is to id what went wrong. i have seen a lot of them rot the intake manifiolds away near the rear intake ports if its a salt water boat.

no guesswork when you do this... you have to know where the water got in from 100 % certain... no maybes